The present invention relates to a sliding latch for windows and doors.
Locking mechanisms for sash windows are known in which, in the closed position, the handle of the locking mechanism engages an opposing receiving element affixed to the adjacent rail of the other window sash. Such latch mechanisms are effective for maintaining a window in a closed position, but are ineffective for holding the window in an intermediate partially open locked position.
This invention arises from a long standing need to allow a window to remain in a position from fully closed to fully open while not allowing the opening to be increased in size from an exterior vantage point. However, the opening can decrease in size, while in a retained unlocked position, thereby providing increased security of an interior home or building by an unsuspecting intruder.
The most common need is for sliding casement windows and doors, however the invention can be applied to other window and door applications.
The following prior United States patents are incorporated herein by reference:
U.S. Pat. Nos. 5,090,750; 6,141,913; 6,178,696; 5,398,447; 5,715,631; 5,127,685; 5,076,015; 5,090,750; and 5,901,499.
The referenced patents have components such as latch mechanisms, cams, and connecting rod members. However, the application and arrangement of the components differs significantly in the modal operation of the invention presented in this disclosure. Also, these patents do not allow for intermediate locked positions of the window or door sash.
The invention provides locking of a sliding window or doorframe member in discrete positions from an interior vantage point. The mechanism for locking the window is at the top most frame member, away from the opening, creating interference for defeating the locking mechanism through a partial opening.
The invention also provides the ability to accommodate tilt-in or pivoting features for cleaning or removal of the window or door. The latch and locking system can be applied to both new and existing window and door systems.
The present invention includes a combination of simple mechanisms for providing locking and retention of windows or doors within their sliding frame members. The invention allows for integration of a complete latching system into new window or door systems and adaptation to existing installations. Existing installations may be limited in some cases to only allow certain features of the invention to be applied. Diametrically opposing latches are utilized to provide latching points on each side of the window or door. The latches are operated from a common center point hub, enabling the latching and lifting or sliding to be accomplished from this vantage point. The invention allows for the latching system to operate in different modes by means of a selector knob constituting a major advantage to the present invention. Without the innovation of retained selection modes, it would not be possible to lock a window or door in an intermediate position. In addition, the capability of intermediate locking positions supports the innovation of a higher level of building security while doors or windows remain partially open.